Abstract Safety and security of life are the two most booming words in the field of transport and manufacturing. The world has emerged from being a just simple form of day to day life to being aeon of mean and daring machines. Thus the safety of the people both inside and outside the vehicle is of prime concern in the car manufacturing industry and scientists are working day in and day out to ensure more and more complex forms of security for the human kind. After dark, your chances of being in a fatal vehicle crash go up sharply, though the traffic is way down. down. Inadeuate illuminatio illumination n is one of the major factors in all the car crashes that occur between midnight and ! a.m. "eadlights provide about #$ meters of visibility on a dark road, but it takes nearly %%$ meters to come to a full stop from %$$ km&hr. At that speed, you may not respond r espond fast enough to an unexpected event, simply because the bright spot provided by your headlights doesn't give you enough time. Thus emerged the night vision systems that use infrared sensors to let driver see as much as ( or ) times farther ahead and help them uickly distinguish among objects.
Introduction The streets of yesterday has turned to be monstrous night mare for the public with demon like vehicle that swift past the roads at very high speeds and the case gets worst in the night with drunken drivers ruling the road with high stake speeds. The reckless accidents that occur on roads during night times mainly owe to the poor visibility and make the drivers rather than driving ahead, predict their way ahead. *ut this is not just the case of drunken drivers but also sensible drivers who find very bad visibility during the wee hours of morning or the odd evenings Thus comes the use of night vision systems which uses infra+red sensors or headlights to provide a clear view of the road ahead and in the coming sections we shall discuss about the detailed working of the night vision systems in automobiles.
Electromagnetic Spectrum *efore going into the night vision systems it is necessary to understand something about liit and the electromagnetic spectrum. "umans are visible only to the rays felling under the visible region of electromagnetic spectrum and are invisible to both the infra+red as well as the ultra violet region of the electromagnetic spectrum. *ut night vision technology makes it possible for the humans to view the rays felling in the infra+red region of the electromagnetic spectrum, that is generally the night vision systems used in automobiles captures the infra+red image of distant obstacles on road as every object emits infra+red rays -heat rays even during night. This image is viewed in a screen and the driver can thus apply the brakes as reuired.
Working Working Of Night Vision Vision Systems in Cars Automotive night vision comes into two flavors/ near and far infrared -I0. The near infrared technology detects the portion of the I0 band nearest to visible light. *ut, the near I0 detector needs an assist. Special bulbs mounted next to the headlights are aimed straight ahead like a car's high beams, but they don't blind other drivers because the human eye is insensitive to the infrared light. The 1I0 system is illuminates the surroundings with infrared light in the wavelength of 2$$ to 3$$ nm. The infrared reflection of objects is captured and converted to a digital signal by a 4harge 4oupled 5evice -445. The digital signal from the 445 is routed to the image processor that
translates it into a format that can be viewed into a black and white head+up display beamed onto the wind+shield. The far infrared technology detects energy farther up the infrared band that is emitted by objects as heat. This far I0 night vision is also called passive, because no special light source is reuired. The special camera these systems use + essentially a phased array of I0 detector elements analogous to the pixels in an ordinary digital camera + creates a temperature pattern called a thermo gram, which is refreshed ($ times a second. The heat from a pedestrian or an animal is much greater than the heat coming to the camera from its surroundings. A signal processor translates the thermo gram data to an image suitable for display on a monitor. It has been found out that neither of the technologies has a clear advantage. *ut, not everyone thinks night vision in cars makes sense. The biggest problem with night vision is that these systems demand that the driver take his&her focus from the road, which is not a good idea, and drivers will just increase their speed, believing themselves to be less at risk, so to avoid this problem the driver is given an automatic warning of the approaching object and thus he doesn't have to look every time on the monitor to check for vehicles and he can completely concentrate on the road while driving. 6ffective algorithms are reuired in order to send a warning to the driver fast enough if a pedestrian is detected.
LC !onitor "sed #y NVS The night vision image does not have color information, and hence monochromatic displays are sufficient. A green phosphor -788 945 display is generally used as the human eye is most sensitive to the color green in this wave length, which falls in the middle of the visible light spectrum. :iewing images in green background also doesn't create much strain to the human eye. The latest generation of 1:5 uses a green yellow 7hosphor -7)( 945 displays, and gives the operator a much more comfortable viewing experience. 4urrent developments have also created a gray scale or black ; white 7hosphor, where the
images can be viewed in black and white.
What is Night Vision System$
The *mw night vision system provides the driver with the black and white image of the driving environment ahead of the vehicle i n the central information display -4I5.*<= night vision is %$$> passive system without active infrared illumination. ?bjects situated ahead of the vehicle are shown in varying degrees of the brightness depending upon the temp of these objects. This enables the driver to detect in good time heat emitting objects s uch as peoples. Animals and the other vehicles.
"se of the Night %ision system in cars
This thermal image is recorded with a far Infrared camera -@I0 via a special imaging sensor which detects the infrared radiations in a specific wavelength range. The *<= system is distinguish from infrared system with active illumination by its long range, and its clearly structured image. Infrared energy coming from an object is focused by the optics onto an infrared detector. A thermal imaging camera can produce a comprehensive image on which the smallest of the temperature difference can be seen. 4ontrary to other technologies, such as e.g. light amplification, that need at least small amount of light to generate an image, thermal imaging needs no light at all. Improve vision in twilight and darkness and the display does not dale by the head lights of the oncoming vehicles. 7ronounced highlighting of process, animals and warm objects as well greater overview of driving situation due to display of course of road beyond that illuminated by headlights. It gives magnified image of the distant objects when driving fast through oom function improved recognisation of objects on bends in the
road through horiontally adjustable image section. It enhances personal safety of dark ways and garage entrance through display of living creature. A far infrared camera in the grill, just over an inch in diameter, senses the temperature of everything in front of the vehicles. A computer then converts the data into an image that appears on the navigation display unit into the dashboard. =armer objects -a pedestrians, an animal appears whiteB cooler objects -parked cars, detritus appears black. =hen the car exceeds 8# mph, the system scans specifically for pedestrians by scanning the road up to %$$ yards ahead of the vehicle. A pedestrian appears with the yellow tint.
&ig' (/ Image obtained on screen.
)' Literature Sur%ey
7re %3)$Cs flares and spot lights were used for operations at night. 5ue to the nature of this early night vision device -1:5, they gave away tactical positions.
Accident scientists show that the driving at the night represents a significant potential danger. In Dermany, some #$ percent of the fatal car accidents happen at night, although an average of the E# percent of all driving is during a day. A similar situation is found in a FS. =ith a 82 percent share of all driving, ## percent of all fatal accidents occur at night. Accidental statistics throughout 6urope as a whole also justif y intensive consideration of the issue of nocturnal driving. According to estimates, approx. #!$,$$$ people injured in the dark and 8(,$$$ are killed. ?ver 8#,$$$ accidents per year involving pedestrians and cyclists occur during the night in the Dermany. The reason are obviousB poor or significantly limited sight conditions on highways and country roads, obstacles or narrow bends which are recognised too late with low beam, inappropriate judgement of the speed or distance due to lack of t he orientation for the eye, driving into the Gblack holeH of the head lights of oncoming traffic, possibly exacerbated by wet, reflecting road surface. ?ur eyes are the first line of the defence against the haards So, the recent innovation to help driver see better at night and in most diverse weather conditions, is the G1ight :ision SystemH The core of this system is @9I0 system thermal imaging camera.*<= is the first 6uropean premium car manufacturer that started to implement the technology in the cars.
1ight vision camera is assembled in the Fnited States, installed in *<= in Dermany and then distributed worldwide. After its utiliation, it goes to waste -6nd of life and then mostly recycled.
*' System Components and escription
The *<= 1ight :ision system consists of the following components/ 1ight :ision camera with camera bracket and camera washer jet 1ight :ision control unit *utton in light switch centre Sensor system
These main components of the night vision system are explained one by one below.
&ig' )/ 4omponent of night vision system.
No'
E+planation %
1ight vision control unit 8
controller display (
controller )
Instrument 4luster #
*utton in light switch centre !
1ight vision camera
*'( Night Vision Camera
&ig' */ 4omponent of night vision system.
The thermal imaging camera consists of a heated optical element and a thermal imaging sensor. The thermal imaging sensor is made up of a multitude of sensor
elements. 6ach display pixel is assigned one such sensor element. The sensor elements generate an electrical signal as a function of the impinging intensity of heat radiation.
The higher the temperature, the brighter the corresponding pixel will be displayed. The heat radiation is converted into electrical signals on the basis of the principle of a change in resistance. The image can be replaced up to !$ times per second. In order to ensure an image of consistent uality, it is necessary for the camera to be calibrated roughly every %8$ seconds. This calibration can take up to approx. $.# seconds. @or this reason, the image may be seen to freee in the display. The 1ight :ision camera is mounted with a bracket directly behind the left ventilation grille on the bumper mounting bracket. The camera is euipped with a sensor which detects heat+emitting objects in the @ar Infrared range -wavelengths from 2 m to %# m. The camera resolution is (8$ x 8)$ pixels. The maximum angle of view is (!J. The calculations for the K*end&curve modeK functions are made in the camera. The camera operates in an ambient+temperature range of + %$)J@ to %2#J@ -)$J4 to L2#J4. The camera and imaging sensor are thermally insulated to provide protection against heat influences from the camera surroundings. The washer jet is screwed to the camera bracket and is situated directly above the camera's front lens. It is directly connected to the headlight washer system and therefore operates in conjunction with the latter. A heater element is incorporated on the inside of the camera+housing cover to prevent the optical element from misting over or freeing up. The heater is activated when the 0ain&light sensor detects precipitation or at temperatures below (8J@ -$J4. A night vision device -1:5 is a device comprising an image intensifier tube In rigid casing, commonly used as military forces. 9ately, night vision technology has become widely available for ci vilian use. @or example, 6nhanced :ision System -6:S have become available for aircraft to help pilots with situational awareness and avoid accidents. These systems are included in the latest avionics packages from manufacturers such as 4irrus and 4essna.
*') Night Vision Control "nit
&ig' ,/ 1ight vision control unit.
The control unit is accommodated in the front 5evice holder behind the glove box. The control unit increases the image data from the camera from (8$ x 8)$ pixels to !)$ x )2$ pixels. ?nly one detail is shown in the control display. !)$ x 8)$ pixels are displayed when the K@ull screenK function is activated while )$$ x 8)$ pixels are displayed for the split screen function. The diagnosis, programming and coding data are transmitted to the camera via the control unit. The camera and the front+lens heater are powered via the control unit. In addition, the control unit converts the symmetrical image data from the camera into a 4:*S signal and, depending on the euipment specification, makes this signal available to either the 1avigation system or the video module. The 1ight :ision control unit is accommodated in the front device holder behind the glove box. The camera+housing cover features a %8+pin plug connection.
The night vision electronics doubles the image created by the night vision camera from (8$ x 8)$ pixels to !)$ x )2$ pixels. ?nly section is shown on the display. =hen G@ull screenH is selected, !)$ x 8)$ pixels are displayed. The split screen display uses )$$ x 8)$ pixels. The night+vision camera is actuated via the 9I1 bus, e.g. for diagnosis. The night+vision electronics convert the symmetrical video signals from the night+vision camera into @*AS signal.
*'* #utton in Light S-itch Center
&ig' ./ Switch button.
The button for switching *<= 1ight :ision on and off is integrated in the light switch center. The following condition can exists/ The rain&light sensor detects sufficient ambient light and driving lights are switched offB *<= night vision is ready for operation approx. 8 seconds after the button in the light switch centre is pressed. The rain&light sensor detects insufficient ambient light and driving lights are switched onB *<= night vision is ready for operation immediately after the button is pressed. In conditions of darkness -underground car park, the driving lights are switched off and the driving speed is less than #km&hB *<= night vision is ready for operation immediately after the button is pressed. *<= night vision cannot be activated when/
The driving lights are switched off,
The sensor detects insufficient ambient light, and The driving speed is greater than #km&h.
?nce the night vision is activated, a message appears in the control display to the effect that the system cannot be used at night without driving lights.
*', /rinciple of Operation
The *<= 1ight :ision camera is a thermal i maging camera, which converts thermal radiation into electronic signals and then into images visible to t he human eye. The thermal image is converted first by the sensor into electrical si gnals and then with the aid of image+ processing software into a visible image in the control display. The sensor elements alter the resistance in proportion to the temperature. The higher the temperature, the higher the electrical signal and the whiter the pixel will be shown. The sensor can generate a new image up to !$ times per second. This results in a softer and clearer image. "eat radiation is absorbed and dissipated by virtually every solid or liuid body. "eat radiation, however, is not visible to the human eye because it belongs in the long+wave infrared range. @rom a physical standpoint, this represents electromagnetic waves with a wavelength of 2 m to %# m. This long+wave infrared radiation is known as @ar Infrared -@I0. The advantage of utiliing radiation in the @ar Infrared range is the greater range compared with 1ear Infrared systems with a wavelength of $.E m to %.) m. These systems reuire illumination with just t his wavelength. 6ssentially, @I0 systems consist of an optical element, a thermal imaging camera, a control unit and a display.
&ig' 0/ 7rinciple of ?peration.
No
E+planation
%
6nvironment ahead of vehicle
8
?ptical element
(
Thermal imaging sensor
)
*<= night vision control unit
#
4entral information display
*'. 1oom Angle Vie- of Camera
=hen the KMoomK function is activated, *<= 1ight :ision automatically switches to a %.# times enlargement of the display at speeds in excess of )) mph -E$ km&h. The cameras angle of view is reduced to 8)J here. Moom is activated automatically again when the speed drops below (E mph -!$ km&h. The camera's angle of view reverts to (!J. Moom is calculated by the camera.
&ig' 2/ Moom angle view.
,' Visibility
1ormal driving+light illumination is approximately (82 ft -%#$ m. The use of *<= 1ight :ision enables heat emitting objects to be detected up to a distance of approx. 32) ft -($$ m. This specified distance is dependent on weather factors. @or example, heavy fog or rain reduces visibility.
&ig' 3/ 4omparison of *<= night vision visibility with different vehicle head lights.
&ig' 4/ The visual and actual Images.
.' Ad%antages and isad%antages
Ad%antages Improved vision conditions of dusk and darkness. 1o daling by head lights of the oncoming vehicles.
"ighlighting of illuminated, heat+emitting objects as pedestrian, cyclists, deer, etc *etter overview of the driving situations.
The oom functions of the object in the far distance at high speeds.
Illumination of the bends&curves -pivoting of image details
Illumination of dark courtyard and garage entrances.
Superior image uality.
Fninterrupted image.
Immune to dynamic thermal environment
isad%antages
The objective of the pedestrian warning algorithm is to accurately detect pedestrians and provide the driver with informative warnings. In the eyes of the driver, the end product of the good system provides a timely warning and possibly, additional information such as position of the pedestrians or an overlaid icon on night vision display.
Although generic image processing algorithms have been addressing similar goals for many years, there are several problems that are uniue to image
processing in automotive application. @or example, It is difficult to distinguish between objects in the foreground and the background of the image the entire image is continuously changing and because pedestrians vary in scale based on their distance to the viewer.
The probability of true warnings -i.e. when the driver is about to hit the pedestrian is low, as it often is in reality, then the odds of the true alarm, can be uite low even for very sensitive warning systems with very high hit rates and low false alarm rates.
Conclusion
In the paper we studied and learnt about the 1ID"T :ISI?1 SNST6< ?@ T"6 *<= which gave us the knowledge about the whole system. *y the study of the paper we got familiarie with the technology used in *<= 1ID"T :ISI?1 SNST6<. Also understood that how to utilie the *<= 1ID"T :ISI?1 feature. @inally, we came to know the benefits to having this technology in the vehicle which can be used to avoid the accidents. ?n the basis of that we conclude that automatic pedestrian warning, in the form of highlighting the pedestrians on the night vision display, is generally helpful in increasing detection distance and accuracy.
5eference
A Simple and effective 5isplay foe night vision system, ?mer Tsimhoni ,
7edestrian detection with night vision system enhanced by automatic warnings by ?mer Tsimhoni,
International Oournal of 6nvironmental Science :olume+(, 1o.%, 8$%8
G*<= 1ight+:ision Available in the # and ! series as of
1ight vision/ reuirements and possible roadmap for @I0 and 1I System.
*<= night vision
G*<= 1ight+:ision Available in the # and ! series as of
http/&&www.bmw.com
*<= night vision application story
